Large Print Processing -- Ideas?

Discussion in 'Color: Film, Paper, and Chemistry' started by newcan1, Nov 22, 2013.

  1. newcan1

    newcan1 Subscriber

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    The largest print size I can process in my Dev-Tec drum is 20x24in. I have gotten it into my head that I would like to try making large prints, say 40x60in. I would likely have to construct appropriate processing equipment. Does anyone have any experience with this (materials, design, etc)?
     
  2. wildbill

    wildbill Member

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  3. artonpaper

    artonpaper Subscriber

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    When I was teaching at Pratt Institute one fellow had his class making 4' x 6' prints from paper rolls in the same darkroom where we made 16" x 20" prints as the largest. He gave me a tour of his set up. They had constructed what are best described as troughs made form clear acrylic sheets (Plexiglass). The troughs were, maybe, 54" by 18" by 18" if I remember correctly. The paper was tacked to the wall and a Beseler enlarger was set up to do horizontal projection. The paper was then rolled into a tube and put in the trough, where it was rolled and unrolled during development and so forth. I personally never used that set up, and didn't see it in action, but the prints were fine.
     
  4. newcan1

    newcan1 Subscriber

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    I can see how using troughs would be a good solution for large b&w prints, and maybe that's all I will do. I was also wondering about color, though, and how one would handle temperature control. Maybe just settle for room temp. development?
     
  5. jnanian

    jnanian Advertiser Advertiser

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    john chiara has a utube vid of him processing very large prints ( col) in a huge drum
    i cant post the link but if you goggles him you will see it ..
    its not his website but U2B ...

    havfun
    john
     
  6. DREW WILEY

    DREW WILEY Member

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    Since you've posted this in the color section, I assume you're referring to color printing. So you have to be conscious of unhealthy fumes, which would make a big open trough processor a bad option. You can use big sections of black ABS plastic irrigation to make your own processing drums. These can be loaded in the dark then even taken outside to a sidewalk or whatever and simply rolled back and forth. But with a bit of imagination, you can build a roller processor base using drive rods and a low RPM gearmotor. My own color drum processor handles up to 30X40,
    and is mounted onto a cart which I push outdoors during good weather.
     
  7. DREW WILEY

    DREW WILEY Member

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    Postscript - I did check that link to the polyethylene black tubes to replace Sonotube carboard cement tubes. The tricks would be how to make
    the light traps on the endcaps. Then you'd want to put a bright battery light inside the capped tube in a darkroom to see just how light tight
    this material actually is (as opposed to thick-walled ABS). My own tubes are made of noryl, which is a highly insulating but quite expensive
    thermoplastic. And it would be important that the endcaps themselves be gluable; otherwise it would be difficult to install secondary light baffles. I also helps to have shallow ridges glued inside the drums, so that rinse water can get behind the print, though you can rinse in a big
    tray afterwards if necessary.
     
  8. wildbill

    wildbill Member

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  9. DREW WILEY

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    One can get almost anything for a price. We have a big industrial plastics dealer around here who specializes in exotic chemical pipe. You name it, even big diameter teflon. But the price per foot would scare the fleas off every dog within a ten mile radius. Cellcore ABS is much cheaper, but quite heavy in big diameters. I've got Sonotube in stock here, but wouldn't trust that simple wax layer to protect the integrity of the tube for long; and pickling it with epoxy would probably unravel it too. So I'm not going to test that idea. The thing to do would see if those plastic substitutes for concrete tube will accept an ABS cap which can be altered to make a light-tight chem fill cap. I won't try this myself, because I've got enough working tubes for now already. But it sounds like a fairly easy and inexpensive way to do it.
     
  10. gleaf

    gleaf Subscriber

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    48 x 96 inch black ABS sheet is available from U.S. Plastics. Glues with standard ABS pipe glue. Shipping from Lorain OH if I remember rightly so destination Chattanooga shouldn't be too unreasonable.
     
  11. DREW WILEY

    DREW WILEY Member

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    Any serious plastics dealer in any major city can sell you all kinds of sheet goods. But then you'd still have to come up with the caps, and they do have to fit perfectly or you'll get both a light leak and chemical leak. Preformed pipe would be a lot easier to deal with. But having a plastic
    which solvent-welds with glue makes life a lot easier than having to heat-weld things together. And some plastics fabricate a lot easier than
    others too. If a big drum becomes especially heavy when it is filled, you just need a little heavier gearmotor to drive. ... and I don't mean those tiny little things like they put in a Jobo. Just remember that your rinse volumes should be quite a bit more than what you need to simply
    develop a print, and that any cap design needs to allow you to fill and drain your chemistry very quickly.